Requirements - If you have China Visa approved before

Hi,

I would like to know what are the requirements if I have china visa approved before? I know I have to submit new picture, application form, and my old passport with approved one. What else do I need to show?

Also, I will be arriving in Beijing on Apr 5, 2013. How soon can I apply? Can I apply as early as Feb 1, 2013 cause I'm also considering about the Chinese New Year. Most of the time embassies have a week long holiday.

Thank you.